Method of obtaining stereophonic sound



Oct. 13, 1953 HQLT-SEELAND 2,655,564

METHOD OF OBTAINING STEREOPHONIC SOUND I Filed Sept. 5, 1951 f 2Sheets-Sheet 1 Ounclaunu Patented Oct. 13, 1953 UNITED STATES PATENTOFFICE,

METHOD OF OBTAINING. STEREOPHONIC SOUND Aage Holt-Seeland, Los'Angeles,Calif.

Applicationseptember 5, 195.1,,SerialNo. 245,149

Norway November 10,1950

4 Claims. 1

This invention relates to cinema performance and more particularly to adevice for connecting tape or track and the sound from another soundsource or group of sources on another sound tapeor track and so forth.Each of these tapes or tracks was then provided with a complete soundreproduction set and with one loudspeaker at a predetermined place inthe cinema. This arrangement gave a realistic performance with ahighwstereophonic effect.

The method was, however, so expensive that it has not been repeated. Ifthetracks should be placed at the edge'of the-film 'in the above casefour trackswere used-each of them. would be too narrow to be practical.A- special tape for the sound tracks was thereforechosen thus raisingthe costs of the films. In addition the performance requires that thecinema is disposing; of several sound reproducing equipments.

The object of the present invention is to solve this problem in such away that a film with a usual sound track can be employed giving asatisfactory result, at the same time as the costs of the necessaryequipment are low.

According to the-present invention each' loudspeaker or group ofloudspeakers is switched on or. off. by means of a stepwise movement ofa perforated sheet of non-conducting material in such a way that certainloudspeakers are on when the perforated sheet is in one position, otherloudspeakers being switched on by the movement of the sheet. Thestepwise movement of the sheet is caused by mechanical or electricalimpulses given by marks on the edge of the film. These marks may bearranged by the person operating the sound recorder or by cutting andhandling of the finished film. The marks may be of different types e. g.a black strip which on the film positive will give a white strip. If abeam of light i directed upon the edge of the film this beam will onlypass through every time a white (transparent) mark is crossing the beam,thus influencing a photoelectric cell placed behind the film so that thecell will give an impulse which by means of an amplifier and an electricmotor or the like would move theperforated sheet one step.

Another way of marking the film consists in stamping out a bit from theedge of the film and passingthe film through a spring contact, thusgiving anelectric impulse to the motor or the like which movesr theperforated sheet eachtime such a mark on the film edge passes thespring- These are only examples of how the contact. him may bemarked andhow these marks may cause the movements of the perforatedsheet.

When the film edge is provided with a mark the member of thecorresponding loudspeaker or loudspeakers which are to be connected forthis part of the film is recorded. In this way therewill be obtained ascheme-with the numbers of the loudspeakers giving the succession forthe connection of the corresponding loudspeakers. If the contacts forthe loudspeakers are placed side byside laterally to the direction ofmotion of the sheet, the sheet may be perforated between thecontacts forthe loudspeaker to be connected.

Thus, accordingto the present invention, an

arrangement for obtaining stereophonicsound- 1 by sound filmperformances comprising a plurality of loudspeakers which automaticallyare connected or disconnected in order thatv the starting point.ofthe-sound inside or outside the screen area shall be adaptedto' thepictures displayed at any time is characterized by a device forconnecting or disconnecting the loudspeakers comprising a. sheet ofelectric insulating material having. perforations that determine theconnection of. the loudspeaker to be connected; said sheet having astepwise movement caused by optical'ormechanical marks on the filmitself, said.

marks by the movement ofthe film through the projecting apparatus beingcapable of giving impulses to an adequate driving device, thusconnecting or disconnecting the desired loudspeakers in relation to themovement of the film through the projector.

Another feature of the present invention consists therein that the filmstrip is provided with the impulse giving marks during cutting orsetting up of the finished film, or simultaneously with the soundrecording.

The invention will now be described by way of example with reference tothe accompanying drawings.

In Fig. 1 is diagrammatically illustrated the layout of fiveloudspeakers.

Fig. 2 is a sectional view on the line I--I in Fig. 1.

Figs. 3 and 4 show film strips with different marks.

In Fig. 1, l is an ordinary film strip with a sound track 2. 3 is anordinary play back head transforming the picture of the sound waves intoelectric oscillations which are amplified in the amplifier 4 and aretransformed into sound by the loudspeakers ll, I2, l3, l4 and [5.Between the amplifier 4 and the loudspeakers is provided a contact table5 where the loudspeakers can be connected or disconnected by means ofthe contacts 6, I, 8, 9 and [0. The strip or sheet l6 consists of anelectric non-conducting material and is inserted between the contacts insuch a way that Without perforations in the strip or sheet; all theloudspeakers would be disconnected. The sheet I6 is, however, providedwith perforations so that at any time the desired loudspeakers areconnected. For instance at the plate indicated by the transverse line I!only the contact 9 will be connected and only the loudspeaker M will befunctioning. If, however, the sheet I6 is moved one step further so thatthe line I8 will be under the contacts, the contact 9 will bedisconnected and the contact 8 connected and only the loudspeaker 13will be functioning.

In the next position [9 the contact 8 will still be connected butsimultaneously the contacts 6 and I will be connected so that theloudspeakers ll, l2 and [3 are in function at the same time. In theposition 20 is the contact 6 disconnected but the contacts 1 and 8 arestill connected so that the loudspeakers l2 and 13 are functioning.

The film l is provided with suitable marks 2| which by passing asuitable device 22, for instance a spring contact or an optical devicelike the play back head 3, are giving impulses to the motor 23 thusmoving the sheet I6 predetermined distances.

In Fig. 2, 5 is the contact table with the perforated sheet l6 insertedbetween the table 5 and the spring contacts 24, 25, 26, 21 and 2B. Inthis figure it is seen how the spring contacts 24, 26 and 21 throughperforations in the sheet [6 are connecting the correspondingloudspeakers with the table 5 which again is electrically connected tothe amplifier, the contacts 25 and 28 and the corresponding loudspeakersbeing disconnected.

In Figs. 3 and 4 is shown film strips with two different kind of markson the films. The strip in Fig. 3 is provided with notches 2| and byusing such marks the device 22 (Fig. 1) could consist of a springcontact device which is connected in all the notches but is disconnectedby the film itself.

The film strip shown in Fig. 4 is marked with black parts (black on thenegative and trans- 4 parent on the print) and the device 22 (Fig. 1)could be an ordinary optical play back head.

Instead ofas mentioned aboveusing an electric non-conducting sheet IS,the sheet could of course consist of a conducting material thusdisconnecting the loudspeakers by perforations.

By employing the method according to the present invention it would besuitable to make a scheme for placing the loudspeakers in a cinemagiving the loudspeakers international numbers and places.

I claim:

1. A system for the reproduction of sound to obtain stereophonic soundfrom a film strip having a sound track by means of a plurality ofloudspeakers selectively connected into the amplifier of the systemaccording to the starting point of the sound inside or outside of thescreen area so that the sound will be adapted to the pictures displayedfrom the film strip at any time, comprising means including a perforatedstrip of electric insulating material, a contact means operativelyassociated with said perforated strip and connected into said amplifier,said contact means including a contact terminal for each of saidloudspeakers adapted to be connected through to said amplifier when aperforation in said sheet is moved into alignment with said terminal,said film strip being provided with marks located thereon, and meansresponsive to said marks on the film strip for advancing said perforatedstrip relative to said contact means thereby efiecting connection of thedesired ones of said loudspeakers with the amplifier.

2. A system as claimed in claim 1 in which the marks on the film stripcomprise notches in an edge of the film strip.

3. A system as claimed in claim 1 in which the marks on the film stripcomprise transparent portions in a dark strip on the edge of the filmstrip.

4. A system as claimed in claim 1 in which the perforated stripcomprises electrically conductive material in which the perforationsconstitute means for disconnecting the loudspeakers in cooperation withthe contact means.

AAGE HOLT-SEELAND.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,909,370 Mallina May 16, 1933 1,953,538 Mittell Apr. 3, 19342,022,665 Halstead Dec. 3, 1935 2,361,490 Mueller Oct. 31, 19442,405,246 Watson Aug. 6, 1946

